1. Field of the Invention
The present invention relates to a polyphase simultaneous observation apparatus, and particularly to apparatus wherein image signals of plural phases are respectively subjected to sampling in scanning line unit while performing high speed scanning in synchronism with repeating phenomena to display an image of specific phase on a display.
2. Description of the Prior Art
Generally, where an object of observation varies with time, it is important for study of properties, research of various characteristics, inspection and the like to observe the varying states.
In the past, where an object of observation varies at a relatively low speed, the states of the object before and after it varies can be easily obtained by performing high speed scanning as in a commercial TV or the like and the object can be observed as a static image. Where an object of observation varies at a high speed, a point sampling method is employed, in which only the image signal of specific phase of high speed repeating phenomena is subjected to sampling while performing plane scanning the required observation area to obrain a static image of specific phase.
However, most of electric machineries are used at commercial frequencies (50 Hz or 60 Hz). Where repeating phenomena over several Hz in the neighbourhood of the commercial frequency to 1 KHz, for example, a magnetic domain of magnetic material of a transformer is directly observed, if the sampling method is used for such slow repeating period, an extremely long period of time was required to obtain a static image of specific phase. For example, it takes 2.times.10.sup.4 seconds=5 hours, 33 minutes and 20 seconds to obtain a static image of specific phase having 10.sup.3 .times.10.sup.3 image elements per image plane by the repeating period of commercial frequency of 50 Hz. There further poses a problem in that an additional long period of time is required to simultaneously observe the state of plural phases where an object of observation varies.